Gas, water and ice: understand what science has already found and where it looks for life outside of Earth | Science and health

The news encouraged the scientific community looking for evidence of extraterrestrial life, but the researchers said more studies are needed on the surface of Venus to show that the phosphine found on the planet is produced by the action of microbes. (Look down)

The astrobiologist and researcher at the National Center for Research in Energy and Materials (CNPEM), Douglas Galante, explains that the discovery is important, but recalls that it is not the first time that phosphine has been discovered on the surface of a planet.

“Phosphine has already been found on the surface of Saturn. Later, scientists discovered that it occurs naturally there, and not by the action of a living being, as it happens on Earth. Now scientists need to find out what is the source of phosphine on Venus. “, explains the astrobiologist.

“To date, we have not found any indisputable evidence of extraterrestrial life. Science has not yet proven the existence of life on other planets,” says Galante. “But where there is water and where there is a source of energy, science is looking for life.”

In addition to phosphine on Venus, science has made other important discoveries recently, such as the discovery of water on Mars and promising conditions on an ice-covered moon of Saturn, Europa. (look down)

“When we talk about life bets outside of Earth, there are researchers who bet on Mars, just as there are those who bet much more on the icy moons of Jupiter and Saturn,” says Galante, who has been investigating the possibilities of Martian soil.

And the stakes don’t stop there. According to one of the authors of the study that discovered phosphine on Venus, the search for life outside of Earth is in full swing, either on Venus or on one of the thousands of planets that science has already discovered in the universe.

“We look for signs of life on exoplanets, we look for gases that we do not expect to be there, and there are many missions looking for possible signs of life in our Solar System,” said Sara Seager, a professor at MIT.

In November 2019, scientists were able to identify the presence of water vapor on Europa, one of Jupiter’s moons. One of the observations showed that the volume of water expelled in the form of steam would be enough to fill an Olympic-size swimming pool in a few minutes.

Similar jets of water have also been detected gushing from the surface of Saturn’s moon Enceladus.

“These moons [Enceladus e Europa] they have huge oceans of liquid water under a crust of ice, a kind of Antarctica with an ocean under its ice, ”explains Galante, who argues that both moons are a condition for microbial life.

Astronomer Cássio Barbosa explained at the time that the discovery was encouraging, mainly because the water found in Europa was in liquid form.

“If someone wants to detect life outside the Earth, they should start looking for places that have water. No ice or steam, liquid water at all. The reason is very simple, life as we know it developed with water as a liquid medium. that, among other things, mediates the exchange of substances at the cellular level ”, Barbosa commented.

However, the favorite of movies and literature when it comes to extraterrestrial life is still Mars.

Galante recalls that science has not yet proven the existence of life on Mars, but says that its fame is mainly due to its similarity to Earth.

“Mars is the closest planet to Earth. It has a reasonable atmosphere for life, although more rarefied, and it has water. In fact, since the dawn of astronomy, marks have already been observed on the surface of Mars in the form of rivers, lakes. and oceans. In other words, we know that Mars had abundant liquid water on the surface in the past, ”says Galante.

• 2020 in space will focus on Mars

Although liquid water was no longer found on the surface of the Martian planet, it still retains water.

“Modern studies show that there is water in the form of ice and even liquid water, but underground,” explains the astrobiologist.

The European Space Agency (ESA) this year sent the jeep Rosalind Franklin on a mission to cross the surface of Mars. Among other things, the jeep will search for underground ice deposits (capable of drilling and acquiring samples) and will have a laboratory for the identification of organic molecules, which can report the activity of microbial life.

It’s worth noting that both the Curiosity mission and the Mars 2020 mission also aim to scan the Martian soil for signs that show life.

Titan, a moon of Saturn, also became of interest in the search for life after a study published late last year revealed that Titan has a hydrological cycle equal to that of Earth, but with the difference that instead For water, the element liquid on the moon is methane and ethane.

According to scientists, one of the prerequisites for life to emerge and develop is to have a liquid medium. Although life on Earth is based on water, liquid methane and ethane could serve as the aqueous medium for the condition of life.

“It is clear that life based on liquid hydrocarbons would be very different from life based on water and there would probably not be much more complex structures than unicellular beings. Even so, it would be the life and reason for all the interest of science ”, explained Cássio Barbosa in his blog about the study of Titan.

Venus was once considered an Earth-like planet, but the hope of finding life on it ended when it was discovered that its surface was the warmest in the Solar System.

“In the past, 4 billion years ago, Venus probably had conditions similar to Earth, but it went into an uncontrolled greenhouse effect, which increased its surface temperature to the extreme. Today, it is an extremely hot planet. , with about 450ºC on its surface, which is why it was considered a ‘dead planet’ ”, explains Galante.

With the discovery of phosphine on its surface this Monday, the fame of ‘dead planet’ promises to stay in the past.

In 2016, NASA had already published a study that hypothesized that Venus may have had a habitable climate and liquid water on its surface early in its existence. It was in this same year, in fact, that the group of scientists who discovered phosphine on Venus this Monday began observing the Venusian planet for signs of life.